Laboratory testing for antiphospholipid syndrome

Pengo, Vittorio; Banzato, Alessandra; Bison, Elisa; Denas, Gentian; Zoppellaro, Giacomo; Bracco, Alessia; Jose, S. Padayattil; Hoxha, Ariela; Ruffatti, Amelia

doi:10.1111/ijlh.12507

Cited by 23 publications

(30 citation statements)

References 25 publications

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“…Platelet count was recorded during a follow‐up visit after 6 months from the clinical event. aPL antibodies were measured as previously described . All of the patients were persistently positive for LAC, aCL and anti‐β 2 GPI antibodies (triple‐positive patients).…”

Section: Methodsmentioning

confidence: 99%

“…Antiphospholipid syndrome (APS) is a systemic, autoimmune disease characterized by venous and arterial thrombosis, fetal loss, and the presence of persistently elevated levels of antiphospholipid (aPL) antibodies (lupus anticoagulant [LAC], anti‐β 2 ‐glycoprotein I [anti‐β 2 GPI] and anticardiolipin [aCL] antibodies) . APS may occur in patients without (primary APS [PAPS]) or with (secondary APS [SAPS]) associated autoimmune diseases.…”

Section: Introductionmentioning

confidence: 99%

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Thrombocytopenia in high‐risk patients with antiphospholipid syndrome

Pontara

Banzato

Bison

et al. 2018

Journal of Thrombosis and Haemostasis

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Background Thrombocytopenia is the most common non-criteria hematological feature in patients with antiphospholipid syndrome (APS). This condition is more common in patients with catastrophic APS (CAPS). Objectives To evaluate the prevalence of thrombocytopenia in a large series of high-risk patients with APS, and to assess the behavior of the platelet count during CAPS. Methods/Patients This was a cross-sectional study in which we analyzed the platelet counts of a homogeneous group of high-risk APS patients (triple-positive). Six of these patients developed a catastrophic phase of the disease, and the platelet count was recorded before the acute phase, during the acute phase, and at recovery. Results The mean platelet count in 119 high-risk triple-positive patients was 210 × 10 L . With a cut-off value for thrombocytopenia of 100 × 10 L , the prevalence of thrombocytopenia was 6% (seven patients). No difference between primary APS and secondary APS was found. In patients who suffered from CAPS, a significant decrease from the basal count (212 ± 51 × 10 L ) to that at the time of diagnosis (60 ± 33 × 10 L ) was observed. The platelet count became normal again at the time of complete remission (220 ± 57 × 10 L ). A decrease in platelet count always preceded the full clinical picture. Conclusions This study shows that, in high-risk APS patients, the prevalence of thrombocytopenia is low. A decrease in platelet count was observed in all of the patients who developed the catastrophic form of the disease. A decrease in platelet count in high-risk APS patients should be considered a warning signal for disease progression to CAPS.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thrombocytopenia in high‐risk patients with antiphospholipid syndrome

Pontara

Banzato

Bison

et al. 2018

Journal of Thrombosis and Haemostasis

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“…[1][2][3] How aPL elicit thrombosis and obstetric complications in patients with APS is not very well understood at the molecular level, [4][5][6] and equally challenging remains the identification of the classes of aPL that best correlate with the clinical manifestations of the disease. [7][8][9] In fact, not only aPL interact with a variety of lipid and protein antigens but, owing to the molecular flexibility of the antigens themselves, subpopulations of aPL targeting the same antigen have been documented in patients with APS. 10,11 Among the types of aPL commonly found in patients with APS, antibodies targeting prothrombin in complex with phosphatidylserine (aPS/PT) have been gaining popularity in recent years because of their strong positive correlation with thrombosis.…”

Section: Introductionmentioning

confidence: 99%

Discovery and characterization of 2 novel subpopulations of aPS/PT antibodies in patients at high risk of thrombosis

et al. 2019

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Anti-phosphatidylserine/prothrombin (aPS/PT) antibodies are often detected in patients with antiphospholipid syndrome (APS), but how aPS/PT engage prothrombin at the molecular level remains unknown. Here, the antigenic determinants of immunoglobulin G aPS/PT were investigated in 24 triple-positive APS patients at high risk of thrombosis by using prothrombin mutants biochemically trapped in closed and open conformations, and relevant fragments spanning the entire length of prothrombin. Two novel unexpected findings emerged from these studies. First, we discovered that some aPS/PT are unique among other anti-prothrombin antibodies insofar as they efficiently recognize prothrombin in solution after a conformational change requiring exposure of fragment-1 to the solvent. Second, we identified and characterized 2 previously unknown subpopulations of aPS/PT, namely type I and type II, which engage fragment-1 of prothrombin at different epitopes and with different mechanisms. Type I target a discontinuous density-dependent epitope, whereas type II engage the C-terminal portion of the Gla-domain, which remains available for binding even when prothrombin is bound to the phospholipids. Based on these findings, APS patients positive for aPS/PT were classified into 2 groups, group A and group B, according to their autoantibody profile. Group A contains mostly type I antibodies whereas group B contains both type I and type II antibodies. In conclusion, this study offers a first encouraging step toward unveiling the heterogeneity of anti-prothrombin antibodies in correlation with thrombosis, shedding new light on the mechanisms of antigen–autoantibody recognition in APS.

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“…Antiphospholipid syndrome (APS) is a heterogeneous autoimmune disorder characterized by arterial or venous thromboembolic events and obstetric complications in association with the persistent laboratory evidence of antiphospholipid antibodies (aPL). [1][2][3] As the clinical manifestations of APS lack specificity, the diagnosis of APS is essentially dependent on the detection of circulating aPL. These aPL are autoantibodies directed against a complex of phospholipids and phospholipid-binding proteins, not directly binding to phospholipids.…”

Section: Introductionmentioning

confidence: 99%

“…LA is a subset of aPL that binds to phospholipid-associated proteins in coagulation complexes and disrupts phospholipiddependent coagulation tests. [1][2][3][4][5][6][7] aPL such as aCL and aβ2GPI antibodies are traditionally detected by ELISA, however newer automated platforms with various solid analytic and detection systems are now available in the diagnostic market.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Diagnosis of Antiphospholipid Syndrome

An¹,

Lim²,

Han³

2017

Clin Exp Thromb Hemost

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The diagnosis of antiphospholipid syndrome (APS) is essentially based on the detection of circulating antiphospholipid antibodies (aPL). Reading and interpretation of aPL profiles may be challenging and results of aPL should be interpreted in view of clinical context. The international diagnostic criteria of APS were developed and revised by international experts and societies, publishing international consensus guidelines on the recommended best practices for technical and performance requirements. Despite these attempts to produce consensus guidelines, some issues related to laboratory testing still remain unresolved. In this review, we want to give an overview of laboratory testing for APS with summary of recent international consensus guidelines for the detection of aPL. Also a brief review of prognostic significance of aPL profile and potential future diagnostic assay is presented.

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Laboratory testing for antiphospholipid syndrome

Cited by 23 publications

References 25 publications

Thrombocytopenia in high‐risk patients with antiphospholipid syndrome

Thrombocytopenia in high‐risk patients with antiphospholipid syndrome

Discovery and characterization of 2 novel subpopulations of aPS/PT antibodies in patients at high risk of thrombosis

Laboratory Diagnosis of Antiphospholipid Syndrome

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